A method for forming on a substrate a relatively thick, densified, essentially non-porous, fine-grained layer of a non-conductive material. The method comprises the steps of vapor depositing onto such substrate a starting material while simultaneously bombarding the substrate with ions of a preselected gas. During the process, the substrate is disposed in the atmosphere of a preselected gas, and an RF field is established between the substrate and an opposing electrode structure to produce a plasma of such gas in the vicinity of the substrate. The substrate is electrically biased to attract ions from the plasma, such ions serving to impact on the substrate and thereby densify the vapor deposit thereon. Preferably, the starting material is one which reacts with the gas ions to form the desired material on the substrate; alternatively, the starting material comprises the desired material, in which case the gas plasma preferably comprises an inert gas.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of commonly assigned U.S. patent application Ser. No. 688,663, entitled "Method for Plasma-Plating a Photoconductive Material onto the Surface of a Substrate", filed May 21, 1976 in the names of Armin K. Weiss and John R. Clarke, which, in turn, is a continuation-in-part of commonly assigned U.S. patent application Ser. No. 636,394, entitled "Method for Plasma-Plating a Dielectric Material onto the Surface of a Substrate", filed Dec. 1, 1975 in the name of Armin K. Weiss, which, in turn, is a continuation-in-part of commonly assigned U.S. patent application Ser. No. 521,011, entitled "Method for Plasma-Plating a Photoconductive Material onto the Surface of a Substrate", filed Nov. 5, 1974 in the name of Armin K. Weiss all of the above applications now abandoned.
An ion plating process wherein a substrate to be plated is suspended in a vacuum chamber filled with an inert gas and radio frequency is supplied to the substrate to be plated to create a plasma which is maintained by the inert gas. Positive DC voltage is then applied to the substrate and negative DC voltage to the filament. Power is then applied to the filament, and upon vaporization of the ion source a plasma of evaporated and ionized deposition material is created between the ion source and the substrate to optimize the deposition of metal plating materials and dielectric materials. The ion source, or vaporizing material is wrapped around a filament which is enclosed within the vacuum chamber. One side of the filament is connected to ground and the vaccum chamber is also ground. The RF power supply feeding power to the substrate is connected to ground and to one side of the wrapped filament and ion source. The DC voltage supply has its positive terminal connected to the RF power line feeding the substrate and its negative terminal joined to the RF power line which is connected to one side of the filament and grounded. Wire mesh grids may be placed between the high temperature ion source and the substrate for more complete control of the plasma, and to direct the plasma flow to certain locations on or around the substrate to be plated. A voltage source may be connected to the grid to control plating on certain parts of the substrate.
A process for coating the surface of a material with a carbonaceous coating by vacuum deposition derives the carbon in substantially pure form from a hydrocarbon gas plasma, the surface to be coated being coupled to an A.C. power source operating at a frequency below 500 kHz at which the electrical impedance of the plasma is substantially non-varying during the deposition process. Because the plasma impedance is substantially constant the process is safe and reproducible and can be carried out without dynamic monitoring and adjustment procedures and there is no requirement for an impedance matching network between the A.C. power supply and the vacuum chamber. Frequencies in the range 300-400 kHz with applied voltages of the order of 1KV or greater have been found to give good results.
Thin film coatings comprising hydrocarbon polymers are deposited on and merged into a substrate by causing secondary ionically activated and electric field energized atomic or molecular ionic species including hydrocarbon species to be directed to a substrate in conjunction with an ion beam of primary energetic ions.
A method of and apparatus for depositing metallic oxide coatings that are highly electrically transmissive and highly electrically conductive onto a substrate. An r.f. signal is employed to develop an ionized plasma of metal and oxygen atoms, the plasma being adapted for deposition onto a large area substrate which preferably includes semiconductor layers thereon. The method and apparatus are particularly adapted for the improved deposition of transmissive and conductive coatings which include low melting point metals onto the surface of plastic, glass or metallic substrates. The deposition may be accomplished in either a continuous or batch process mode.
A method for etching or chemically treating a surface of an article utilizing a radio frequency wave ion generating apparatus which provides a thin disk shaped plasma is described. The plasma disks can have a relatively large diameter (on the order of magnitude 50 centimeters). The plasma disks can be created without using a static magnetic field. The radio frequency waves are preferably microwaves or UHF. The method is particularly useful for ion or free radical irradiation of the surface provided in the plasma or for irradiation of the surface by ions accelerated outside a cavity containing the plasma. Disk plasmas are created over a wide pressure range (10.sup.-4 Torr to 1 atmosphere) and are highly ionized at low pressures. An apparatus adapted for treating a surface of an article with ions from a plasma is also described. The method and apparatus are preferably used for treating a surface forming part of an integrated circuit.
